1. Field of the Invention
The present invention relates in general to a flow rate measuring apparatus and more particularly to an apparatus to which the theory "Karman vortex street" is practically applied.
2. Description of the Prior Art
It is known that, under certain conditions, a "Karman vortex street" is shed in the wake of a bluff body when a flow of fluid is perpendicular to the body. The shedding of vortexes occurs periodically first from one side of the body and then from the other in accordance with the velocity of the flow. Thus, by detecting or counting the number of the vortexes created by the body in a unit time, the flow rate of the fluid can be measured. For this purpose, an electrically operated Karman vortex detector (or detectors) is employed, which is disposed in a fluid conduit downstream of the vortex generating body. However, some of the flow rate measuring apparatus of this type have a weak point in stably and lastingly supporting the detector in the fluid conduit in which a fluid to be measured flows, as will be understood hereinafter.